The first surgical isolators were developed for use in gnotobiotics where germ-free laboratory animals were obtained by delivering such animals from their parents by Caesarean section directly into an aseptic environment.
European patent application no. 01650109 is directed to a method of rearing a bird of specified contamination free status. The method of this application comprises housing a bird as a parent bird, surgically removing an egg in its shelf from the parent bird prior to transfer of the egg to the cloaca in the parent bird, incubating the egg and hatching the egg to produce a laying bird. The application also relates to the production of avian eggs of specified contamination free status.
The present invention is concerned with a surgical isolator and cradle for use in sterile procedures for obtaining eggs and birds of specified germ-free status.
In this specification, the term “contamination free/germ-free” is used very broadly and relates to many pathogens and infections that can be carried by birds, particularly, poultry such as chickens and turkeys which are used widely to produce flocks of birds for breeding to produce fertile eggs for commercial production and to produce eggs and meat for human consumption. Further, such eggs and birds are used in the manufacture of a wide range of biological substances including vaccines, antibodies, monoclonal antibodies, fibroblasts and proteins, both for therapeutic and prophylactic use in people and animals. They are further used extensively for diagnostic tests and the production of transgenic eggs and birds. Many of these uses require eggs and/or the birds produced from them to be free of either all or specified contaminants such as infections, including a variety of species of parasite, bacteria, mycoplasma, viruses, retroviruses, prions, DNA and RNA fragments. Sometimes, the viruses can be small viruses including picoma and parvo viruses. Some of the bacteria from which eggs are often contaminated include Clostridia and Enterobacteria. There are many non-pathogenic organisms that should be controlled. Similarly, many of the microorganisms which include parasites, aerobic and anaerobic bacteria, commensal species and species associated with the gut, are undesirable. Similarly, mycoplasma, viruses including retroviruses, prions, fungi, yeast and moulds are also undesirable.
Therefore, the term “specified contamination free” or “germ-free status” could include some or all of these and is much broader than just free of specified pathogens. For example, conventional specific pathogen free (SPF) are not specified free from some viruses and indeed can be contaminated with bacteria. Thus, for certain uses, these may be sufficient. The use to which the eggs and the birds are to be put will determine the contaminants that the egg or bird must be free of. Conventional germ free and some SPF eggs are derived by treating fresh naturally laid eggs with chemicals, including disinfectants and antibiotics, and placing them in isolators. Such naturally laid eggs are taken from selected parent stock birds. White these methods have been relatively successful in the production of SPF eggs, they have not been truly successful in producing what are contaminant free eggs. However, the chemicals are not able to eliminate contamination from, for example, bacteria entering the pores of the eggshell immediately after laying and before disinfection. Contamination of eggs, whether SPF, germ-free or gnotobiotic, results in loss of compliance with specifications and, in many instances, toss of commercial value and a utility.